Viscosimeter



Patented Mar. 16, 1937 UNITED STATES PATENT OFFICE VISCOSIMETER. A

I Application May 25, 1936, Serial No. 81,638

9 Claims.

' This invention relates to viscoslmeters of the type in which samplesof a liquid whose viscosity is to be tested are introduced into a narrowspace between two relatively movable surfaces, the resistance torotation under similar conditions serving as a measure of the viscosityof any given film, .and my object is to provide apparatus of this typewhich will enable an operator to quickly. test successive samples ofliquid at a standard temperature without requiring the taking of exactlymeasured samples. I attain my object by means of a construction whichmay be briefly described as follows:

The basis of the device comprises .an imperl5 forate bowl shaped memberand a second imperforate member concentric withand normally'positionedwithin the bowl with its external surface slightly spaced from theinternal surface of the latter to form a space to contain a thin film ofthe liquid to be tested. While the width of this space may vary I findfifteen one-thousandths of an inch is satisfactory for one type ofpatent leather varnish.

The two members are relatively rotatable and for convenience may bereferred to as the stator and rotor. The bowl will ordinarily be the'stator and the other member the rotor. The rotor and stator are movableaxially relative to one another to facilitate the introduction of liquidinto the stator. -The stator is waterjacketed for cooling purposes.

The invention is hereinaftermore specifically described and isillustrated in the accompany 7 ing drawing in which Fig. 1 is a verticalsection of the device; and

Fig. 2 a plan view of the same with the driving pulley omitted.

In the drawing like numerals of reference indicate corresponding partsin the different 11g l The device comprises two main parts abowl shapedmember and a second member concentric therewith between which isdisposed a thin fllm oi' the liquid to be tested. One of these parts isa rotor and the other a stator. Pref erably the bowl shaped member I isthe stator and the member H the rotor. By bowl shaped is to beunderstood that the interior of the stator is of such a shape that whenthe rotor, which has a corresponding exterior shape, is moved axiallyrelative to the stator the distance between the surfaces is varied andthus the thickness of any liquid contained between the two. In. epreferred form both surfaces are suhstan y conical. The stator is formedon or connected with the base 2. The upper edge or rim of the statorextends laterally and terminates in the annular trough 4.

The base 2 is provided with the bearing support 6, which is formed witha bridge carrying the bearing 1. 'The bearing support 6 is formed withthe depending annular flange-8 which fits closely within the rim 5 ofthe base 2 to thus position the support 6 relative to the base 2 andtherefore to the stator. lifting screws 9 are 10 threaded through thebearing support 6 andbe'ar upon the upper surface of the rim 5. Theseserve as a means for backing off the bearing support 6 in case itbecomes stuck or gummecl up with the liquid being tested. 1

In the bridge of the bearing support the bearing l is centrallypositioned in axial alinement with the stator and through the bearingthe spindle It! extends so as to be rotatable in and slidable lengthwiseof the bearing. To the 0 spindle is securedthe rotor II which in itslower part is concentric with the stator and is formed with an upwardlyextending rim l2 extending well above the rim of the bowl of the stator.

Set in a recess 1 nthe lower end .of the rotor 25 in alinement with theaxis thereof is a ball 13 forming a thrust bearing, which ball isadapted to run in a recess formed in the upper end of the block I whichis preferably threaded into the apex of the bowl to form a bearing for.the 30 ball l3. The block is thus readily renewed in case of wear. Itmay be also used to adjust the space left between the adjacent surfacesof the rotor and stator as may be required. Usually the ball and bearingwill be so positioned rela- 35 tive to one another that a space of aboutfifteen one-thousandths of an inch is left between the adjacent surfacesof the rotor and stator.

The base 2 of the stator is hollow so that it forms a water jacket forthe exterior of the 40 stator. Within the hollow base is fitted thecylindrical balile I5, from the upper rim of which depends thefrusto-eonical bafile It. A water inlet I! is provided leading into thespace outside the cylindrical baflie while the outlet 18 45 communicateswith the space within the cylindrical bame. Ice water entering throughthe inlet I1 is thus compelled to pass in a stream over the outersurfaces of the stator, thus efficiently cooling the same.

To the upper end of the spindle I0 is secured a pulley l9, around whichis wrapped a cable 2| which passes over the sheave 20 carried by anysuitable support and has a weight 22 secured to its end. The weight thusserves to rotate the rotor H.

- The operation of the device is substantially as follows:Coolingliquid, usually ice water, is kept continually circulating through thebase so that the bowl of the stator is maintained at a temperature veryclose to the freezing point. The rotor and bearing support are thenremoved from their position on the base and a quantity of the hot liquidto be tested is poured into the bowl l. The actual quantity poured inneeds tube a little more than enough to fill the gap between the statorand the rotor when the latter is in position and a suitable quantity iseasily estimated by eye or otherwise approximately measured. The bearingsupport is then replaced and the rotor and spindle pushed downwardthrough the bearing until further descent is prevented by the ball l3taking up its position on the block I l. During this descent, whichoccupies only a few seconds of time the fluid in the bowl is forced toform a thin film occupying the space between the rotor and stator andcompletely filling it,'excessive fluid overflowing into the trough Q.The rotor is then driven by means of the cord and weight and the timeoccupied by one or more revolutions measured. This time is the measureof the viscosity of the fluid. The rotor assembly and bearing supportare removed, the rotor and bowl of the stator wiped clean, whereupon theinstrument is ready for a repetition of the operation on a new sample.

Each repetition of the operation; that is, pouring in the sample,assembling the instrument,

timing the rotation, dismantling the instrument and cleaning it occupiessome two to three minutes.

It is found in practice that the fluid is cooled from temperatures ashigh as 550 F. to freezing point in the short time required to assemblethe instrument. The instrument is thus of special value when theprogress as regard to viscosity of a heated fluid, occurring in aprocessingvessel, is to be followed up to a desired final state which isindicated by the attainment of a. certain viscosity. This instrumentthus makes it possible to control the preparation of fluids, such asvarnishes, which are so thin at the processing temperature that theyoffer little real resistance to the motion of the rotor but which have avery considerable viscosity at 32 F.

The cooling of the rotor by filling its interior with ice water may beresorted to as a supplement to the cooling of the stator.

What I claim as my invention is:

1. A viscosimeter comprising an imperforate bowl-shaped member having anopen top; a second imperforate member concentric with and, complementingthe first and normally positioned within the bowl with its outer surfaceslightly spaced from the inner surface of the bowl, the said membersbeing axially displaceable relative to one another so that liquid placedin the bowl when the said members are separated is squeezed into a thinfilm between the members when the latter are restored to their normalco-operative position.

2. A viscosimeter according to claim 1 in which the bowl-shaped memberis formed with its upper margin below the level of the top of the othermember when the two are in co-operative position to provide an overflowfor surplus liquid.

3. A viscosimeter comprising an imperforate bowl-shaped stator; a basecarrying said stator; a bearing supported from the said base in axialalinement with the stator; a spindle journaled in and slidable throughthe bearing; an imperforate rotor concentric with the stator and securedto the spindle; and a thrust bearing between the rotor and statordefining the axial position of the rotor relative to the stator.

4. A viscosimeter comprising an imperforate bowl-shaped stator; a waterjacket surrounding the stator; baffles in the water jacket to directflow over the outer surface of the stator; an imperforate rotorconcentric with the stator and mounted thereon to slide axially thereof;and a thrust bearing between the rotor and stator defining the axialposition of the rotor relative to the stator.

5. A viscosimeter comprising an imperforate bowl-shaped stator; animperforate rotor concentric with the stator and mounted thereon toslide axially thereof; and a thrust bearing between the rotor and statordefining the axial position of the rotor relative to the stator, the rimof the bowl being positioned below the top of the rotor when the rotorand stator are in co-operative position to provide an overflow forsurplus liquid.

6. A viscosimeter comprising an imperforate bowl-shaped stator; animperforate rotor concentric with the stator and mounted thereon toslide axially thereof; a thrust bearing between the rotor and statordefining the axial position of the rotor relative to the stator; the rimof the bowl being positioned below the top of the rotor when the rotorand stator are in co-operative position; and an annular trough to whichsaid rim discharges.

7. A viscosimeter comprising an imperforate bowl member having asubstantially conical inside surface and an open top; a secondimperforate member having a substantially conical outer surface similarto that of the inside of the bowl, the said members being relativelyrotatable and also axially displaceable to vary the spacing of theaforesaid surfaces; and adjustable means for setting the minimumspacing.

8. -A viscosimeter according to claim 1 in which the bowl-shaped memberis formed with its upper margin below the level of the top of the othermember when the two are in co-operative position to provide an overflowfor surplus liquid; and a water jacket is formed about the exteriorsurface of the bowl-shaped member.

9. A viscosimeter comprising an imperforate bowl-shaped stator member;an imperforate rotor member concentric with and complementing the statormember and normally positioned within the stator with its outer surfaceslightly spaced from the interior surface of the said stator; a basecarrying the stator; a bearing supported from said base; a spindlejournalled in and slidable through said bearing and to which the rotormember is secured, the said rotor member being therefore axiallydisplaceable relative to the stator JAMES N. GOODIER.

